1. Field of the Invention
The present invention relates to a wedge element to immobilize objects in a box of cardboard, corrugated or similar solid fiber material, with a square or rectangular cross-section, particularly for shipping and transportation of said objects, such boxes featuring a flat bottom of polygonal shape (generally rectangular or square) and four faces or side walls.
The technical domain of the invention is that of machinery for the manufacture, processing or closing of packaging materials and that of the manufacture and application of wedge materials for such packaging.
The present invention concerns more particularly a wedge element intended for being placed inside boxes used for the preparation and shipping of orders for single or multiple articles and more generally for boxes the content of which occupies a variable volume from one box to the next, and, most of the time, significantly less than the total volume of the box, in which case said wedging material serves to immobilize the items inside the useful volume of the box.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
It is known that boxes of this type are created by machines from one or several flanks of pliable rigid sheeted material and that their upper part features various flaps and turned-down pieces assembled by gluing or adhesive tape or a lid fitted over said upper part. A characteristic of these boxes is that they offer a constant volume once they have been produced and closed.
Several means are applied by the users or are integrated into the box forming or closing machines to fasten by wedges the objects which vary by number and unit volume from one box to another.
One is familiar, for example with wedging means constituted by heat-shrinking plastic film where one or several layers are secured to the bottom or the side walls of the box during its shaping. After the box has been filled, these films are lowered onto the pile of objects and then retracted by passing through a heating tunnel.
Such a process presents several disadvantages. As a matter of fact:                this heat-shrink plastic film must necessarily be separated from the carton packaging prior to possible collection and recycling of the corresponding waste; this collection is a complex and very costly operation;        this wedging material is itself expensive;        its application is difficult and requires either complex automated machines or a great number of man-hours; the cost of these operations is therefore high.        
Also known is the use of polystyrene particles or other light materials which are spread inside the box after insertion of the objects, in order to fill unused space.
Another fastening method consists of using inflatable plastic pockets which are placed inside the boxes to fill any unused space.
One is also familiar with the use of chips, particles, pelletized balls, . . . of paper, carton or wood which are put, in various forms, inside the boxes to fill unoccupied space between the objects.
Such production methods also present several disadvantages. As a matter of fact:                the distribution dosage of these wedging materials so they fill exactly the unused space is an operation that is difficult to automate which requires either complex automated machines or a great number of man-hours; the cost of these operations is therefore high;        collection of these materials after opening the packaging requires a number of different elements and is thus an operation not easily taken care of by the end user.        
And one is also familiar with wedging elements presenting themselves in the form of a sheet of cardboard, corrugated or equivalent solid fiber featuring a central part which is put into contact with the upper surface of the pile of objects placed inside the box and flexible flaps on at least two sides of the central part of the sheet which are turned down and fastened, for instance by gluing, against the inside face of the side walls of said box.
Such wedging elements are, for example, described in the document EP-1 197 436. Documents FR-2 828 169, DE-2 02 04 975, EP-1 452 453, EP-0 251 945, U.S. Pat. No. 6,216,871, FR-1 575 635, FR-919 469, U.S. Pat. No. 3,108,731, U.S. Pat. No. 2,883,046, and FR-2 770 447 illustrate other implementations of wedging elements of this type or the technological background.
The implementation of the wedging element described in document EP-1 197 436 presents numerous advantages:                This wedging element is not meant to fill up all the unused space inside the box; the quantity of material used is always the same and remains moderate, even when the previously packaged objects occupy only a very small portion of the volume of the box;        This sheet can be made of a material similar to that used for producing the box itself, thereby greatly simplifying the recycling operations of the waste resulting from the elements constituting such a packaging.        Placement and fastening of this sheet inside the box are mechanical operations which can be automated.        
But the implementation of such a wedging element also presents some inconveniences.
As a matter of fact:                the flat central part of the wedging sheet must be sufficiently sturdy and rigid to resist the constraints involved in the transportation of the box and maintain in a stable manner the products contained in it; under these conditions, it is often necessary to exert considerable efforts to deform it so that the largest portion of its surface will be in contact with the upper surface of the pile of objects; these efforts are inevitably transmitted to some of these objects and may damage them, if some of them are fragile;        when the lid of the box is removed, this wedging sheet constitutes an obstacle which prevents direct access to the packaged goods; for that this sheet needs to be torn away, but this operation is made difficult due to the absence of a grip area; to make this operation easier, it is known that the manufacturers usually put a plastic ribbon, called a pull strap, on the lower surface of box lids so as to facilitate opening of the lid by tearing the lid along the line created by this ribbon; the problem is that this pull strap can easily be put by the manufacturers only on the face of the lid on which grooves (also called channels) are made which mark the location of the folds of the flaps; on a lid, this face corresponds properly to the lower face; in the case of a wedging sheet as described, the face on which the grooves are made corresponds to the upper face of the wedge; it is thus not possible to easily place a pull strap on the bottom face of the wedge;        the material used for producing such a wedging sheet is most often corrugated board; this material, constituted in its so-called “single flute” version by 3 layers of paper (two flat sheets enclosing a corrugated sheet), poses a particular problem due to its anisotropic character: in effect, the folding of the various flaps along the grooves positioned perpendicularly to the flutes of the material does not pose a particular problem, whereas the folding of the flaps along the grooves positioned parallel to the flutes of the material has a tendency to deviate from the theoretical folding line created by the groove for the benefit of a most often polygon folding line, corresponding to the smallest effort needed to fold the flap taking into account the positions of the waves of the flute in the folding zone; the result of this deviation is an incorrect wedge geometry with dimensions between the turned-down flaps which may vary by significant proportions (in the order of the thickness of the wedging sheet, which is to say several millimeters);        the folding zone which connects the flaps to the central portion of the sheet is a zone of fragility; if special precautionary measures are not taken during the production of this wedge sheet, there exists a major risk of tearing of the material along this fold.        
The problem at hand is therefore to provide a wedge in the form of a cardboard sheet, corrugated board or equivalent solid fiber material featuring a central portion which is put into contact with the upper surface of the pile of objects placed inside the box and flexible flaps, on at least two sides of the sheet, which are meant to be turned down and fastened, for example by gluing, to the internal face of the sidewalls of the box, this sheet:                must have a central portion that is sufficiently sturdy and rigid to resist the constraints during the transportation of the box and properly keep the product in these conditions, but must also be sufficiently pliable so that the largest portion of its surface can be put into contact with the upper surface of the pile of objects without exerting any major stress on these objects;        must allow a precise folding of the flaps along the theoretical folding line at their articulation with the central portion of the sheet, without making this articulation overly fragile.        
The device described in document FR-2 828 169 does not allow to efficiently resolve the problem previously described. This device is constituted by a plate made of a semi-rigid material, such as cardboard or corrugated board, comprising a polygonal central portion with at least two parallel sides that are articulated by folding lines, strips or flaps the sides of which that are opposite the side walls of the container or box containing the items to be shipped are provided with an adhesive enabling them to become integral with said walls. It is pointed out, incidentally, that the central portion features folding lines parallel to two of its parallel sides which make it possible to deform said plate to apply it to portions of different heights of mixed lots of items to maintain in position in the boxes. According to the implementation illustrated in FIG. 3 of document FR-2 828 169, the polygonal central portion of the wedge plate features only two folding lines or grooves parallel to its short sides. Said central portion features, on the other hand, two weakening lines close together parallel to its large sides, however, these are not folding lines but perforating lines associated with a pull strap provided with a tab or “snake head” for traction.
Such a layout of the wedge sheet does not resolve the problem of efficient wedging of unusually shaped objects.
As a matter of fact,                either the wedge sheet is made of material that is too rigid and, in this case:        it cannot mold very closely the uneven upper surface of the pile of objects;        it can exert significant pressure on said upper surface so that certain fragile objects may get crushed or damaged by this pressure.        or the wedge sheet is made of too soft material and risks being split open if the score lines yield under the pressure, leading to the tearing of said wedge sheet as it is being pushed into the box.        